Low profile extraction electrode assembly

ABSTRACT

A low profile extraction electrode assembly including an insulator having a main body, a plurality of spaced apart mounting legs extending from a first face of the main body, a plurality of spaced apart mounting legs extending from a second face of the main body opposite the first face, the plurality of spaced apart mounting legs extending from the second face offset from the plurality of spaced apart mounting legs extending from the first face in a direction orthogonal to an axis of the main body, the low profile extraction electrode assembly further comprising a ground electrode fastened to the mounting legs extending from the first face, and a suppression electrode fastened to the mounting legs extending from the second face, wherein a tracking distance between the ground electrode and the suppression electrode is greater than a focal distance between the ground electrode and the suppression electrode.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate to the field ofsemiconductor and solar cell processing, and more particularly to a lowprofile, high voltage insulator for facilitating close proximitycoupling of extraction electrodes in an ion beam implanter.

BACKGROUND OF THE DISCLOSURE

Ion implantation is a technique for introducing conductivity-alteringimpurities into a workpiece such as a wafer or other substrate. Adesired impurity material is ionized in an ion source of an ion beamimplanter, the ions are accelerated to form an ion beam of prescribedenergy, and the ion beam is directed at the surface of the workpiece.The energetic ions in the beam penetrate into the bulk of the workpiecematerial and are embedded into the crystalline lattice of the workpiecematerial to form a region of desired conductivity.

Conventional ion beam implanters often include a number of extractionelectrodes, including a suppression electrode and a ground electrode,configured to extract an ion beam from an ion source and to manipulate(e.g., focus and/or direct) the ion beam in a desired manner. Theextraction electrodes are commonly mounted on an electrode positioningsystem including a motorized manipulator arm for facilitating selectivemovement of the extraction electrodes relative to the ion source. Forexample, if an ion beam is out of focus when initially extracted fromthe ion source, the manipulator arm may reposition the extractionelectrodes in a corrective manner to focus the ion beam in a desiredmanner.

Due to a large difference in electrical potential between a groundelectrode and a suppression electrode during operation of an ionimplanter electrically insulating the electrodes from one another isperformed to prevent or mitigate the flow of electrical currenttherebetween. Particularly, the ground electrode is separated from thesuppression electrode with an electrical insulator. A shortest distancemeasured along a surface of the insulator between the electrodes,commonly referred to as a “tracking distance,” achieves a desired degreeof physical separation and electrical insulation between the electrodes.Maintaining a specific distance, hereinafter referred to as a “focaldistance,” between a ground electrode and a suppression electrode isgenerally performed in order to focus an extracted ion beam in a desiredmanner.

Focal distances are typically shorter than tracking distances. Thus, inorder to maintain a desired focal distance between a ground electrodeand a suppression electrode while simultaneously providing a trackingdistance of desired length between the electrodes, ground electrodes anda suppression electrodes are often coupled to one another using complexmounting arrangements including multiple connective and supportivestructures (e.g., support arms, mechanical fasteners, etc.) havingassociated manufacturing tolerances. When aggregated, thesemanufacturing tolerances can result in an undesirable offset oreccentricity between a ground electrode and a suppression electrode,adversely affecting the focus and/or alignment of an extracted ion beam.Additionally, the various supportive and connective structures used tocouple a ground electrode and a suppression electrode may be formed ofvarious materials having different coefficients of thermal expansion,and/or may be subject to uneven heating during operation of an ionimplanter. This may lead to incongruous thermal expansion andcontraction of the supportive and connective structures, furtherexacerbating eccentricity between the ground electrode and suppressionelectrode.

It is with respect to these and other considerations the currentimprovements may be useful.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form further described below in the Detailed Description.This Summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is this Summary intended asan aid in determining the scope of the claimed subject matter.

An exemplary embodiment of a low profile extraction electrode assemblyin accordance with the present disclosure may include an insulator, aground electrode fastened to a first side of the insulator, and asuppression electrode fastened to a second side of the insulatoropposite the first side, wherein a tracking distance between the groundelectrode and the suppression electrode is greater than a focal distancebetween the ground electrode and the suppression electrode.

Another exemplary embodiment of a low profile extraction electrodeassembly in accordance with the present disclosure may include aninsulator having a circular main body, three mounting legs extendingfrom a first face of the main body and spaced apart from one anotheraround an axis of the main body, and three mounting legs extending froma second face of the main body opposite the first face and spaced apartfrom one another around the axis of the main body, the three mountinglegs extending from the second face offset from the three mounting legsextending from the first face around the axis of the main body, the lowprofile extraction electrode assembly further including a groundelectrode fastened to the three mounting legs extending from the firstface, a suppression electrode fastened to the three mounting legsextending from the second face, first and second outer particulateshields extending from the ground electrode radially outward of theinsulator, and first and second inner particulate shields extending fromthe ground electrode radially inward of the insulator, the first outerparticulate shield radially overlapping the second outer particulateshield and the first inner particulate shield radially overlapping thesecond inner particulate shield.

An exemplary embodiment of an ion implanter in accordance with thepresent disclosure may include a source chamber, an ion source disposedwithin the source chamber and configured to generate an ion beam, and alow profile extraction electrode assembly disposed within the sourcechamber adjacent the ion source and configured to extract and focus theion beam, the low profile extraction electrode assembly including aninsulator, a ground electrode fastened to a first side of the insulator,and a suppression electrode fastened to a second side of the insulatoropposite the first side, wherein a tracking distance between the groundelectrode and the suppression electrode is greater than a focal distancebetween the ground electrode and the suppression electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, various embodiments of the disclosed apparatus willnow be described, with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic plan view illustrating an exemplary embodiment ofa beam line ion implanter in accordance with the present disclosure;

FIG. 2a is a front isometric view illustrating an exemplary extractionelectrode assembly in accordance with an embodiment of the presentdisclosure;

FIG. 2b is a rear isometric view illustrating the exemplary extractionelectrode assembly shown in FIG. 2 a;

FIG. 3 is a cross sectional side view illustrating the exemplaryextraction electrode assembly shown in FIGS. 2a and 2 b.

DETAILED DESCRIPTION

A low profile extraction electrode assembly for facilitating closeproximity coupling of electrodes in an ion beam implanter in accordancewith the present disclosure will now be described more fully hereinafterwith reference to the accompanying drawings, wherein certain exemplaryembodiments of the extraction electrode assembly are presented. Theextraction electrode assembly may be embodied in many different formsand is not to be construed as being limited to the embodiments set forthherein. These embodiments are provided so this disclosure will bethorough and complete, and will fully convey the scope of the extractionelectrode assembly to those skilled in the art. In the drawings, likenumbers refer to like elements throughout.

FIG. 1 is a schematic diagram of a beam-line ion implanter 100(hereinafter “the implanter 100”). Those skilled in the art willrecognize the implanter 100 is one of many examples of beam-line ionimplanters capable of producing and directing an ion beam for dopingsubstrates. Thus, the insulator described herein is not limited toapplication solely in the exemplary implanter 100 shown in FIG. 1.Additionally, the implanter 100 is not restricted to “beam-line”designs, and could include other types of ion implanters based on plasmaimmersion, flood, or other plasma source designs, for example.

Generally, the implanter 100 may include a source chamber 102 configuredto generate ions for forming an ion beam 104. The source chamber 102 mayinclude an ion source 106 where a feed gas supplied to the ion source106 is ionized. This feed gas may be, or may include or contain,hydrogen, helium, other rare gases, oxygen, nitrogen, arsenic, boron,phosphorus, aluminum, indium, gallium, antimony, carborane, alkanes,another large molecular compound, or other p-type or n-type dopants, forexample. The generated ions may be extracted from the ion source 106 bya series of extraction electrodes, including a suppression electrode 108and a ground electrode 110, configured to focus and direct the ion beam104 as further described below. The extracted ion beam 104 may be massanalyzed by a mass analyzer 112 including a resolving magnet 114 and amasking electrode 116 having a resolving aperture 118. The resolvingmagnet 114 may deflect ions in the ion beam 104 so ions having a desiredmass-to-charge ratio associated with a particular dopant ion species areallowed to pass through the resolving aperture 118. The undesired ionspecies do not pass through the resolving aperture 118 since theundesired ion species are blocked by the masking electrode 116.

Ions of the desired ion species may pass through the resolving aperture118 to an angle corrector magnet 120. The angle corrector magnet 120 maydeflect ions of the desired ion species and may thus convert the ionbeam from a diverging ion beam to a ribbon ion beam 122 having generallyparallel ion trajectories. The implanter 100 may further includeacceleration and/or deceleration units in some embodiments. Accelerationand deceleration units may be used in ion implant systems to speed up orslow down an ion beam. Speed adjustment is accomplished by applyingspecific combinations of voltage potentials to sets of electrodesdisposed on opposite sides of an ion beam. As an ion beam passes betweenthe electrodes, ion energies are increased or decreased depending on theapplied voltage potentials. Since the depth of an ion implant isproportional to the energy of an impinging ion beam, beam accelerationmay be desirable when performing deep ion implants. Conversely, whereshallow ion implants are desired, beam deceleration may be performed toensure impinging ions travel just a short distance into a workpiece. Theexemplary implanter 100 shown in FIG. 1 includes a deceleration unit124.

An end station 126 of the implanter 100 may include a platen 128configured to support one or more workpieces, such as a substrate 130,disposed in the path of the ribbon ion beam 122 so ions of a desiredspecies are implanted into the substrate 130. The substrate 130 may be,for example, a semiconductor wafer, solar cell, etc. The end station 126also may include a scanner (not shown) for moving the substrate 130 in adirection perpendicular to the long dimension of the ribbon ion beam 122cross-section, accordingly distributing ions over the entire surface ofthe substrate 130. Although a ribbon ion beam 122 is illustrated, otherembodiments of the implanter 100 may provide a spot beam. The entirepath traversed by the ion beam is evacuated during ion implantation. Theimplanter 100 may further include additional components known to thoseskilled in the art and may incorporate hot or cold implantation of ionsin some embodiments.

Still referring to FIG. 1, the suppression electrode 108 and the groundelectrode 110 may be coupled to one another by a low profile, highvoltage insulator 132 (hereinafter “the insulator 132”) for electricallyinsulating the suppression electrode 108 from the ground electrode 110while holding the suppression electrode 108 at a desired distance fromthe ground electrode 110 as described in greater detail below. Theground electrode 110 may include a mounting arm 134 coupled to amanipulator arm 136 of an ion beam manipulator 138 (hereinafter “themanipulator 138”) located within the source chamber 102. The manipulator138 may be provided for selectively adjusting the positions of theinterconnected suppression electrode 108, insulator 132, and groundelectrode 110 (hereinafter referred to collectively as “the extractionelectrode assembly 140”) relative to the ion source 106 for focusing theextracted ion beam 104 in a desired manner. In an alternativeembodiment, the mounting arm 134 may extend from the suppressionelectrode 108 instead of from the ground electrode 110. In anotheralternative embodiment, the mounting arm 134 may be omitted and themanipulator arm 136 may be coupled directly to the ground electrode 110or to the suppression electrode 108. In another alternative embodiment,the manipulator may be located partly or entirely outside of the sourcechamber 102.

Referring to FIGS. 2a and 2b , front and rear exploded isometric viewsillustrating the extraction electrode assembly 140 of the implanter 100are shown. The insulator 132 of the extraction electrode assembly 140may be formed of an electrically insulating, temperature resistantmaterial suitable for use within the source chamber 102 (FIG. 1), suchmaterials including quartz, ceramics such as alumina and zirconia,various thermoplastics, and high temperature thermosets such as epoxy.The insulator 132 may include a main body 133 having a first pluralityof mounting legs 142 a, 142 b, 142 c extending from a first face 143thereof, and having a second plurality of mounting legs 144 a, 144 b,144 c extending from a second face 145 thereof opposite the first face143. In the illustrated example, the main body 133 is circular. Othershapes are contemplated and may be implemented as further describedbelow. The mounting legs 142 a, 142 b, 142 c may be circumferentiallyspaced 120 degrees apart from one another around an imaginary centralaxis Q of the main body 133. Similarly, the mounting legs 144 a, 144 b,144 c may be circumferentially spaced 120 degrees apart from one anotheraround the imaginary central axis Q. The mounting legs 144 a, 144 b, 144c may be circumferentially offset from the mounting legs 142 a, 142 b,142 c by 60 degrees around the imaginary central axis Q. The insulator132 may have an overall thickness (i.e., a maximum dimension in adirection parallel to the imaginary central axis Q) in a range of 1millimeter to 20 millimeters, for example.

The mounting legs 142 a, 142 b, 142 c of the insulator 132 may befastened to the ground electrode 110, such as by mechanical fasteners(not shown) extending through the mounting legs 142 a, 142 b, 142 c andthrough respective mounting holes 146 a, 146 b, 146 c in the groundelectrode 110. Similarly, the mounting legs 144 a, 144 b, 144 c of theinsulator 132 may be fastened to the suppression electrode 108, such asby mechanical fasteners (not shown) extending through the mounting legs144 a, 144 b, 144 c and through respective mounting holes 148 a, 148 b,148 c in the suppression electrode 108. Assembled thusly, the extractionelectrode assembly 140, and particularly the insulator 132 of theextraction electrode assembly 140, may provide desired electricalinsulation between the suppression electrode 108 and the groundelectrode 110 while also maintaining a desired “tracking distance” and adesired “focal distance” between the suppression electrode 108 and theground electrode 110, wherein “tracking distance” is defined herein as ashortest distance measured along a surface of the insulator 132 betweenthe suppression electrode 108 and the ground electrode 110, and wherein“focal distance” is defined herein as a distance measured along theimaginary central axis Q between the suppression electrode 108 and theground electrode 110. Particularly, as indicated by the dashed line 150in FIG. 2a , the tracking distance between the suppression electrode 108and the ground electrode 110 may be the sum of a length of one of themounting legs 142 a extending from the first face 143 of the main body133, the length of one of the circumferentially adjacent mounting legs144 a extending from the second face 145 of the main body 133, thelength of the circumferential segment of the insulator 132 extendingbetween the mounting leg 142 a and the mounting leg 144 a, and thethickness of the main body 133. Expressed another way, the trackingdistance between the suppression electrode 108 and the ground electrode110 may be the sum of the overall thickness of the insulator 132 and thelength of the circumferential segment of the insulator 132 extendingbetween the mounting leg 142 a and the mounting leg 144 a.

Thus, owing to the circumferential offset of the mounting legs 144 a,144 b, 144 c relative to the mounting legs 142 a, 142 b, 142 c, thetracking distance between the suppression electrode 108 and the groundelectrode 110 may be significantly greater than the focal distancebetween the suppression electrode 108 and the ground electrode 110. Forexample, if the diameter of the insulator 132 is 4.88 inches and theoverall thickness of the insulator 132 is 0.67 inches, the trackingdistance between the suppression electrode 108 and the ground electrode110 may be 3.23 inches, whereas the focal distance between thesuppression electrode 108 and the ground electrode 110, indicated by thedashed line 152 in FIG. 3, may be 0.197 inches. This relationship isachieved in the absence of additional structures or components (i.e.,structures or components other than the insulator 132), such as complexmounting arm arrangements employing multiple couplings, for connectingand/or insulating the suppression electrode 108 and the ground electrode110. Since the suppression electrode 108 and the ground electrode 110are coupled directly to one another by the insulator 132 in the absenceof any other intervening structures or components, eccentricity betweenthe suppression electrode 108 and the ground electrode 110, otherwisepossibly caused by uneven thermal expansion and/or contraction of suchintervening structures or components during operation of the implanter100, is avoided.

In various alternative embodiments, the insulator 132 may be implementedwith a greater or fewer number of mounting legs (i.e. greater or fewerthan three mounting legs 142 a, 142 b, 142 c extending from the firstface 143 of the main body 133 and/or greater or fewer than threemounting legs 144 a, 144 b, 144 c extending from the second face 145 ofthe main body 133). In one example, two mounting legs may extend fromthe first face 143 of the main body and two mounting legs may extendfrom the second face 145 of the main body 133, wherein the two mountinglegs extending from the first face 143 are circumferentially spaced 180degrees apart from one another around the imaginary central axis Q, thetwo mounting legs extending from the second face 145 arecircumferentially spaced 180 degrees apart from one another around theimaginary central axis Q, and the two mounting legs extending from thefirst face 143 are circumferentially offset from the two mounting legsextending from the second face 145 by 90 degrees around the imaginarycentral axis Q. In another example, four mounting legs may extend fromthe first face 143 of the main body and four mounting legs may extendfrom the second face 145 of the main body 133, wherein the four mountinglegs extending from the first face 143 are circumferentially spaced 90degrees apart from one another around the imaginary central axis Q, thetwo mounting legs extending from the second face 145 arecircumferentially spaced 90 degrees apart from one another around theimaginary central axis Q, and the four mounting legs extending from thefirst face 143 are circumferentially offset from the four mounting legsextending from the second face 145 by 45 degrees around the imaginarycentral axis Q.

In various alternative embodiments, the insulator 132 may be implementedwith a main body 133 having a shape other than circular. For example,the main body 133 of the insulator 132 may be oval, rectangular,star-shaped, Z-shaped, H-shaped, irregularly shaped, etc. Suchalternative embodiments of the insulator 132 may be implemented withpluralities of mounting legs similar to the mounting legs 142 a, 142 b,142 c and 144 a, 144 b, 144 c, with a first plurality of mounting legsextending from a first face 143 of the main body 133 for connection tothe ground electrode 110 and a second plurality of mounting legsextending from a second face 145 of the main body 133 for connection tothe suppression electrode 108, wherein the mounting legs extending fromthe second face 145 of the main body 133 are offset from the mountinglegs extending from the first face 143 of the main body 133 in adirection orthogonal to a central axis of the main body 133 (e.g., thecentral axis Q shown in FIGS. 2a and 2b ), thus creating a non-linearpath along a surface of the insulator 132, wherein a tracking distancebetween the ground electrode 110 and the suppression electrode 108 ismeasured along such non-linear path.

Referring to FIG. 2a , the suppression electrode 108 may have a pair ofannular, radially spaced apart, outer particulate shields 160 a, 160 bextending from a front face 162 thereof toward the ground electrode 110.Referring to FIG. 2b , the ground electrode 110 may have a pair ofannular, radially spaced apart, inner particulate shields 164 a, 164 bextending from a rear face 166 thereof toward the suppression electrode108. As best shown in the side cross section of the extraction electrodeassembly illustrated in FIG. 3, the outer particulate shields 160 a, 160b and the inner particulate shields 164 a, 164 b may be disposed in aradially overlapping arrangement with the outer particulate shield 160 adisposed radially outside of the inner particulate shield 164 a and withthe outer particulate shield 160 b disposed radially inside of the innerparticulate shield 164 b. Arranged thusly, the outer particulate shield160 a and the inner particulate shield 164 a may define a tortuous path168 for mitigating the migration of particulate from the externalenvironment 170 to the insulator 132. Similarly, the outer particulateshield 160 b and the inner particulate shield 164 b may define atortuous path 172 for mitigating the migration of particulate from theion beam 104 to the insulator 132. The outer particulate shields 160 a,160 b and the inner particulate shields 164 a, 164 b may thus cooperateto mitigate the accumulation of particulate on the insulator 132,wherein such accumulation could otherwise increase the electricalconductivity of the insulator 132 and compromise the ability of theinsulator 132 to electrically insulate the suppression electrode 108from the ground electrode 110 in a desired manner.

In view of the foregoing description, those of ordinary skill in the artwill appreciate numerous advantages provided by the extraction electrodeassembly 140, and particularly the insulator 132, relative to otherextraction electrode assemblies and insulators commonly employed in ionbeam implanters. For example, a first advantage conferred by thedisclosed insulator 132 is a desired tracking distance and a desiredfocal distance may be maintained between the suppression electrode 108and the ground electrode 110 in the absence of additional structures orcomponents (i.e., structures or components other than the insulator132), such as complex mounting arm arrangements employing multiplecouplings, for connecting and/or insulating the suppression electrode108 and the ground electrode 110. Another advantage conferred by thedisclosed insulator 132 is, since the suppression electrode 108 and theground electrode 110 are coupled directly to one another by theinsulator 132 in the absence of any other intervening structures orcomponents, eccentricity between the suppression electrode 108 and theground electrode 110, otherwise possibly caused by uneven thermalexpansion and/or contraction of such intervening structures orcomponents during operation of the implanter 100, is avoided. Yetanother advantage conferred by the disclosed insulator 132 is reducedcost and complexity relative to other extraction electrode insulatorshaving complex structures involving multiple mounting arms and/ornumerous points of attachment for achieving a desired tracking distance,a desired focal distance, and adequate electrical insulation.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are intended to fall within the scope ofthe present disclosure. Furthermore, although the present disclosure hasbeen described herein in the context of a particular implementation in aparticular environment for a particular purpose, those of ordinary skillin the art will recognize its usefulness is not limited thereto and thepresent disclosure may be beneficially implemented in any number ofenvironments for any number of purposes. Accordingly, the claims setforth below are to be construed in view of the full breadth and spiritof the present disclosure as described herein.

1. A low profile extraction electrode assembly comprising: an insulator;a ground electrode fastened to a first side of the insulator; and asuppression electrode fastened to a second side of the insulatoropposite the first side; wherein a tracking distance between the groundelectrode and the suppression electrode is greater than a focal distancebetween the ground electrode and the suppression electrode, and whereinthe tracking distance between the ground electrode and the suppressionelectrode is greater than an overall thickness of the insulator.
 2. Thelow profile extraction electrode assembly of claim 1, wherein theinsulator comprises: a main body; a mounting leg extending from a firstface of the main body and fastened to the ground electrode; and amounting leg extending from a second face of the main body and fastenedto the suppression electrode; wherein the mounting leg extending fromthe second face of the main body is offset from the mounting legextending from the first face of the main body in a direction orthogonalto an axis of the main body.
 3. The low profile extraction electrodeassembly of claim 2, wherein the mounting leg extending from the firstface of the main body comprises a plurality of spaced apart mountinglegs extending from the first face of the main body, the mounting legextending from the second face of the main body comprises a plurality ofspaced apart mounting legs extending from the second face of the mainbody, wherein the plurality of spaced apart mounting legs extending fromthe second face of the main body is offset from the plurality of spacedapart mounting legs extending from the first face of the main bodyaround the axis of the main body.
 4. The low profile extractionelectrode assembly of claim 3, wherein the main body is circular.
 5. Thelow profile extraction electrode assembly of claim 4, wherein theplurality of mounting legs extending from the first face of the mainbody comprises three mounting legs spaced apart from one another by 120degrees around the axis of the main body, the plurality of mounting legsextending from the second face of the main body comprises three mountinglegs spaced apart from one another by 120 degrees around the axis of themain body, and wherein the plurality of mounting legs extending from thesecond face of the main body are offset from the plurality of mountinglegs extending from the first face of the main body by 60 degrees aroundthe axis of the main body.
 6. The low profile extraction electrodeassembly of claim 1, wherein the ground electrode and the suppressionelectrode are fastened directly to the insulator.
 7. The low profileextraction electrode assembly of claim 1, further comprising: a firstouter particulate shield extending from the ground electrode radiallyoutward of the insulator; and a second outer particulate shieldextending from the suppression electrode radially outward of theinsulator; the first outer particulate shield radially overlapping thesecond outer particulate shield.
 8. The low profile extraction electrodeassembly of claim 1, further comprising: a first inner particulateshield extending from the ground electrode radially inward of theinsulator; and a second inner particulate shield extending from thesuppression electrode radially inward of the insulator; the first innerparticulate shield radially overlapping the second inner particulateshield.
 9. The low profile extraction electrode assembly of claim 1,further comprising: a first outer particulate shield extending from theground electrode radially outward of the insulator; a second outerparticulate shield extending from the suppression electrode radiallyoutward of the insulator; a first inner particulate shield extendingfrom the ground electrode radially inward of the insulator; and a secondinner particulate shield extending from the suppression electroderadially inward of the insulator; the first outer particulate shieldradially overlapping the second outer particulate shield and the firstinner particulate shield radially overlapping the second innerparticulate shield.
 10. A low profile extraction electrode assemblycomprising: an insulator comprising: a circular main body; threemounting legs extending from a first face of the main body and spacedapart from one another around an axis of the main body; and threemounting legs extending from a second face of the main body opposite thefirst face and spaced apart from one another around the axis of the mainbody; the three mounting legs extending from the second face offset fromthe three mounting legs extending from the first face around the axis ofthe main body; a ground electrode fastened to the three mounting legsextending from the first face; a suppression electrode fastened to thethree mounting legs extending from the second face; first and secondouter particulate shields extending from the ground electrode radiallyoutward of the insulator; and first and second inner particulate shieldsextending from the ground electrode radially inward of the insulator;the first outer particulate shield radially overlapping the second outerparticulate shield and the first inner particulate shield radiallyoverlapping the second inner particulate shield.
 11. An ion implanter,comprising: a source chamber; an ion source disposed within the sourcechamber and configured to generate an ion beam; and a low profileextraction electrode assembly disposed within the source chamberadjacent the ion source and configured to extract and focus the ionbeam, the low profile extraction electrode assembly comprising: aninsulator; a ground electrode fastened to a first side of the insulator;and a suppression electrode fastened to a second side of the insulatoropposite the first side; wherein a tracking distance between the groundelectrode and the suppression electrode is greater than a focal distancebetween the ground electrode and the suppression electrode, and whereinthe tracking distance between the ground electrode and the suppressionelectrode is greater than an overall thickness of the insulator.
 12. Theion implanter of claim 11, wherein the insulator comprises: a main body;a mounting leg extending from a first face of the main body and fastenedto the ground electrode; and a mounting leg extending from a second faceof the main body and fastened to the suppression electrode; wherein themounting leg extending from the second face of the main body is offsetfrom the mounting leg extending from the first face of the main body ina direction orthogonal to an axis of the main body.
 13. The ionimplanter of claim 12, wherein the mounting leg extending from the firstface of the main body comprises a plurality of spaced apart mountinglegs extending from the first face of the main body, the mounting legextending from the second face of the main body comprises a plurality ofspaced apart mounting legs extending from the second face of the mainbody, wherein the plurality of spaced apart mounting legs extending fromthe second face of the main body is offset from the plurality of spacedapart mounting legs extending from the first face of the main bodyaround the axis of the main body.
 14. The ion implanter of claim 13,wherein the main body is circular.
 15. The ion implanter of claim 14,wherein the plurality of mounting legs extending from the first face ofthe main body comprises three mounting legs spaced apart from oneanother by 120 degrees around the axis of the main body, the pluralityof mounting legs extending from the second face of the main bodycomprises three mounting legs spaced apart from one another by 120degrees around the axis of the main body, and wherein the plurality ofmounting legs extending from the second face of the main body are offsetfrom the plurality of mounting legs extending from the first face of themain body by 60 degrees around the axis of the main body.
 16. The ionimplanter of claim 11, wherein the ground electrode and the suppressionelectrode are fastened directly to the insulator.
 17. The ion implanterof claim 11, further comprising: a first outer particulate shieldextending from the ground electrode radially outward of the insulator;and a second outer particulate shield extending from the suppressionelectrode radially outward of the insulator; the first outer particulateshield radially overlapping the second outer particulate shield.
 18. Theion implanter of claim 11, further comprising: a first inner particulateshield extending from the ground electrode radially inward of theinsulator; and a second inner particulate shield extending from thesuppression electrode radially inward of the insulator; the first innerparticulate shield radially overlapping the second inner particulateshield.
 19. The ion implanter of claim 11, further comprising: a firstouter particulate shield extending from the ground electrode radiallyoutward of the insulator; a second outer particulate shield extendingfrom the suppression electrode radially outward of the insulator; afirst inner particulate shield extending from the ground electroderadially inward of the insulator; and a second inner particulate shieldextending from the suppression electrode radially inward of theinsulator; the first outer particulate shield radially overlapping thesecond outer particulate shield and the first inner particulate shieldradially overlapping the second inner particulate shield.
 20. The ionimplanter of claim 11, wherein one of the ground electrode and thesuppression electrode is coupled to a manipulator for selectivelyadjusting a position of the extraction electrode assembly.